Balancing systems for centrifuging machines



United States Patent Office 3,494,471 Patented Feb. 10, 1970 3,494,471BALANCING SYSTEMS FOR CENTRIFUGING MACHINES Antonio R. Grippo, 5427Santa Tome St., Buenos Aires, Argentina Continuation-impart ofapplication Ser. No. 430,119,

Feb. 3, 1965. This application May 20, 1968, Ser.

Int. Cl. B01d 33/06 US. Cl. 210-463 5 Claims ABSTRACT OF THE DISCLOSUREA balancing ring system for rotatable receptacles, such as the rotarybasket of a centrifugal clothes-drying machine, comprising a pluralityof stacked fiexible annular chambers against the inner wall of saidbasket, and a liquid partially filling these chambers, the said chambersbeing adapted to be deformed by clothes or the like whereby the liquidthere will be circumferentially displaced to balance the distribution ofweight in said basket.

CROSS REFERENCE TO RELATED APPLICATIONS This application is acontinuation-in-part of US. application Ser. No. 430,119 filed Feb. 3,1965, now abandoned.

BACKGROUND OF THE INVENTION Field of the invention The present inventionrelates to a balancing ring system for rotatable receptacles such as forexample a centrifugal action clothes-drying machine.

Although reference is made to clothes-drying machines, it is to beexpressly understood that the present invention is also applicable toany other centrifugal action machines which require a dynamic balancingof the centrifuging component.

Description of the prior art Centrifugal clothes-drying machinesgenerally comprise a rotatable tub or basket driven by a mechanism whichcomprises an electric motor to which the basket is connected through avertical shaft transmitting thereto the axial rotary motion forcentrifuging the clothes to be treated, said basket having a pluralityof perforations for discharging the water saturating the clothes duringthe centrifuging operation.

In machines of the aforesaid type, the vibrations imparted to the basketduring the centrifuging process and particularly at the start thereof,due to an unbalanced distribution of the clothes in the basket,frequently create a series problem. This problem is present even whenthe clothes are properly distributed in the spinning basket, thevibrations causing jerks transmitted to the basket at the time ofstarting the centrifugation, with a resulting multiplication of thevibrations imparted to the driving shaft, to the extent that in mostcases it has been found necessary to limit the speed of rotation toabout 600 rpm. in order to avoid damage to the machine.

It is well known that the higher the rotary speed of the basket, themore effective and accelerated will be the clothes-drying process. Thisexplains the need of an arrangement which will make it possible to raisethe speed of rotation considerably. The improvements provided by thepresent invention make it possible to obtain normal operation of amachine with a 25 to 30 cm. radius basket rotating at a speed of about1500 r.p.m. with a resulting higher degree of drying of the dryingprocess.

Various devices and arrangements have been proposed in the past in orderto solve the same or similar problems although none of the known deviceshave been successful in offering a simple efiicient solution. Much tothe contrary the known devices and arrangements for example containmovable counterbalancing components which are displaced by centrifugalforces acting thereon as a result of unbalanced loads. These knowndevices have many drawbacks two of which are that the unbalanced loaddoes not act directly against the movable components in order to producetheir displacement, and that these components are of rather large sizeand therefore the finite variations in balancing effect introduced bytheir change in position does not entirely agree with the infinitevariations of the unbalancing force.

A further type of known device incorporates the use of thyxotropicsubstances housed in an annular ring surrounding the outside of acentrifuging drum. By not enabling the unbalanced load, such as a bundleof clothes, to act directly thereagainst, the compensating effect ofthis arrangement is indirect and accordingly subject to error; what ismore these thyxotropic substances only become effective after certainspeeds have been reached so that on starting, they provide no balancingeffect.

Devices somewhat more smilar to those of the present invention have beenprovided, these devices including an annular body of for example watersurrounding the centrifuging drum. This type of device more trulybalances any eccentricity of the load although they do not avoid thebasket from suffering an angular displacement in a vertical plane whichis still a drawback sufliciently important to keep manufacturers fromoffering a clothesdrying machine capable of operating at the mentionedspeeds and under the conditions given. This last drawback has beenrecognized in the art and accordingly an apparatus for achievingsynchronized dynamic balance and overcoming such a drawback has beenprovided. This apparatus comprises flexible receivers for example forwater, between a container and a casing, wherein both said container andsaid casing are movable. This type of device overcomes the problem ofvertical angular displacement although its construction is extremelycostly its assembly most difficult and what is more it does not actdirectly in response to the unbalanced load, inasmuch as the mentionedreceivers are positioned outside the container. In other words, thistype of device incorporates a balancing means external to the containeror basket and which must be incorporated into the centrifugal drierduring manufacture, it not being possible to incorporate this known typeof balancer into a conventional machine, without carrying out asubstantial modification.

A further drawback of this type of device is that soapy water becomesentrapped between the container and the casing. This soapy waterdecomposes quite quickly and gives off a bothersome smell and what ismore does much harm to the components in contact therewith.

A still further drawback of this type of device is that the drive forceexerted on the clothes basket is transmitted thereto through thementioned balancing means and accordingly these must be madesufficiently strong to withstand such a stress, obviously this necessarystrength is a feature which reduces the balancing effect inasmuch as atruer balance will obviously be obtained if a very flexible material isused. All these known devices incorporating a body of liquid around therotary basket are provided with a rigid wall for transmitting the forceexerted by the unbalanced clothes to this liquid. This featureintroduces a further drawback in addition to those already mentioned forthis type of device. This new drawback resides in that the liquiddisplacement produced for balancing the load is not located exclusivelyin that part where the eccentric load is active.

3 SUMMARY OF THE INVENTION The object of the present invention is toprovide means for automatically neutralizing any unbalance in thedistribution of the clothes, or other load, within the centrifugingbasket by direct action of the unbalanced clothes, or other load, on thementioned means.

In accordance with the illustrated embodiment of the present inventionthere is provided a centrifugal clothesdrying machine comprising arotary basket for containing clothes, said rotary basket defining aninner wall face, of a predetermined circumference, means for rotatingsaid basket about a substantially vertical axis, said inner Wall facebeing substantially parallel to said verticl axis, a plurality ofannular flexible members axially stacked one above the other againstsaid inner wall face and resting on each other, said flexible membershaving an outer circumference substantially coinciding with thecircumference of said inner wall face, at least the portion of each oneof said flexible members facing the middle of said basket being adaptedto yield and deform under pressure directly exerted by clothes withinsaid basket and in contact with the portion of said flexible membersfacing the middle of said basket, and a liquid charge at least partiallyfilling said chambers for automatically balancing the weight in saidbasket and minimizing the vibration thereof during rotation of saidbasket.

BRIEF DESCRIPTION OF THE DRAWINGS In order to facilitate thecomprehension of the present invention, reference will now be made tovarious embodiments, by way of example, in relationship to theaccompanying drawings, wherein:

FIG. 1 is a schematic vertical section of a conventional centrifugalclothes-drying and washing machine embodying the improvement inaccordance with the present invention; and

FIG. 2 is a perspective vie-w, partially in section, of one of theflexible members in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring in the first place toFIG. 1 there is illustrated an outer casing for a conventionalcentrifugal clothesdrying machine which as is known in the art isgenerally also a clothes washing machine. The outer casing 10 rests onthe floor by means of legs 11 and has defined on its upper wall portion12 an opening 13 adapted to be closed by means of a lid 14 connected tothe upper wall portion 12 by means of a hinge 15.

Within the casing 10 there is mounted an electric motor 16 having anoutput shaft 17 connected to a shaft coupling 18 in turn connected to aclutch 19. Shaft coupling 18 is connected directly and permanently tothe gears of gear box 21 having an output drive shaft 20 for rotatingpallets 27. Clutch casing 19' is rigid with gear box casing 21' alsorigid with basket 22. In this way two modes of operations are possible;a first one with clutch 19 free and a second with clutch 19 engaged. Inthe first mode, electric motor 16 will drive pallets 27 independently atbasket 22, while in the second mode, basket 22 will be rotated due toits connection to clutch casing 19'. Clutch 19 is of the electromagnetictype, so that when energized coupling 18 is drivingly connected to 19'.In the first mode, the mechanical connection between electric motor 16and pallets 27 is established through output shaft 17, shaft coupling18, gear box 21 and drive shaft 20, while in the second mode, motor 16is connected to basket 22 through output shaft 17, shaft coupling 18,clutch casing 19' and gear box casing 21'. The rigid connection betweengear box 21 and basket 22 (which houses drive shaft 20) is rotatablysupported in bearing 38 mounted on a plate member 23, secured by meansof springs 24 to casing 10. These means for rotating basket 22 are alsosupported at 25 on the lower wall portion 26 of casing 10.

Basket 22 comprises a bottom wall 28, a lateral wall 29 and an upperbell shaped portion 41 defined by a lateral wall portion and an upperwall portion and an upper wall portion; lateral wall 29 and upperportion 41 are secured to one another for examle by nuts and bolts (notillustrated). At the level of this connection, that is to say at theupper part of the lateral wall 29, perforations such as 30 are providedin order to enable the water contained within basket 22, duringcentrifugation, to be ejected therefrom.

The upper wall portion of upper bell shaped portion 41 defines anopening 31 through which basket 22 can be loaded with clothes.

Obviously as is well known in the art, it is necessary to provide waterin-feed and outlet means as well as sealing means in order to avoid thatwater come into con tact with the electrical drive means hereinabovereferred to.

It is to be understood that the foregoing description with reference tothe corresponding illustration is intended to only schematicallyrepresent a conventional centrifuging clothes-drying machine, without inany way implying that the present invention can only be used with atheoretical machine such as so far referred to.

Dealing specifically now with the improvement in accordance with thepresent invention, there are provided within basket 22, a plurality ofhollow annular flexible members 32, 32", 32", 32 axially stacked oneabove the other against the inner wall face 33 of basket 22 and restingone upon the other, this last feature plus the fact that these flexiblemembers have an outer circumference which substantially coincides withthe circumference of said inner Wall face 33, thereby providing a tightfit therebetween, enables them to remain in the position illustrated,during all phase of operation. Flexible members 32, 32, 32", 32, 32 arepreferably made of rubber although the object of the present inventionis also achieved by having these flexible members comprise a rigid outerportion 34 (FIG. 2) and a flexible inner portion 35. Obviously, theflexible portion 35 will face the middle of the basket when flexiblemembers 32, 32', 32", 32", 32 (FIG. 2) are positioned within basket 22.

Although hollow flexible members 32, 32, 32", 32", 32 have beenillustrated as being of approximately oval radial section, it is to beunderstood that the section thereof could be rectangular, square, or anyother shape which fulfills the objects to be achieved, and each flexiblemember defines an annular chamber.

As may be seen from FIG. 2, these flexible members are independent onefrom the other so that they can be easily incorporated into anyconventional centrifugal clothes-drying machine of the typeschematically illustrated in FIG. 1 by merely introducing the first oneof these annular members 32' and resting it against the bottom wall 28in the position illustrated in FIG. 1.

Thereafter a second annular member 32" is inserted through openings 13and 31 and positioned to rest upon the already inserted annular member32'. This procedure is followed with the remaining annular members whichare to be inserted within basket 22. Although in FIG. 1 annular members32', 32", 32" and 32 have been illustrated as being of the same size, itis possible for them to be of slightly different sizes without thisaffecting the compensating effect thereof. Furthermore, and although inFIG. 1 the annular members 32, 32", 32" and 32 are not spread over theentire lateral wall 29, it is possible, and in no way a disadvantage, tohave them extend entirely from bottom wall 28 to the level ofperforations 30, or over the entire upper portion 29.

On outer portion 34 at substantially regular intervals there are adheredspacing strips 36. Each one of these strips may be made of rubber orother suitable material. Fundamentally, the object of these strips is todefine channels 37 therebetween through which the water within basket 22can move freely. As is known in the art, most centrifuging drums such asbasket 22 are generally supported exclusively by their lower portion sothat when subject to a centrifugal action the upper portion does notonly rotate but suffers a circumferential displacement due to thecentrifugal force acting on the free upper portion. It is for thisreason that the water contained within basket 22 is carried upwardswithin basket 22 and ejected through perforations 30. In orderto permitthis upward movement of water, channels 37 are defined.

In order to obtain the 'counterbalancing effect desired, the chambersdefined flexible members 32 are partially filled with a liquid, forexample ,water. Obviously, it is desirable that the water containedwithin flexible members 32 rotate at the same speed as the basket. Dueto inertia, upon commencement of rotation of the basket, the water willlag behind for some time until friction makes the entire mass of waterrotate at the same speed as the basket. If this time interval is to bereduced, it is desirable to increase the friction between the innerfaces of flexible members 32 and the fluid contents thereof, to whicheffect strips 36 are also suitable. As the outer circumference of theflexible member 32 substantiallly coincides with the circumference ofthe inner wall face 33, the existance of strips 36 will cause flexiblemembers 32 to rest against inner wall face 33 with a slight outer radialforce whereby outer portion 34 will be circumferentially undulated, suchundulation defining internal protrusions within flexible members 32 andchannels 37 on the outside thereof. Such protrusions serve to increasethe friction between the internal faces of the flexible members 32 andthe liquid contents of the flexible members.

Although strips 36 serve to increase the friction between flexiblemembers 32 and the liquid contents thereof it is possible to include,within flexible members 32, internal deflectors 39 provided for the samepurpose (see cut away portion of FIG. 2 which represents a possiblealternative) Generally, these internal deflectors 39 are of flexiblematerial and are secured on a strap 40, only part of which is seen inFIG. 2. During construction. of flexible members 32, and before theannular flexible member is closed by welding both ends, strap 40 withinternal deflectors 39 thereon, is inserted within flexible members 32.

In operation any mass of clothes which may become eccentricallypositioned will act against one or more of the flexible members 32,depending on the height of the eccentric mass. From this it will alreadybe seen that water displacement is achieved exclusively by direct actionof the clothes on the flexible members and that this water displacementwill only occur at those points where such as eccentric mass acts.

In this way cause and effect are diametrically opposite and actvirtually in the same horizontal plane. It is important to recognizethis last fact inasmuch as it is one of the beneficial features ofproviding a plurality of flexible members 32. Normal house-hold clotheswashing and drying machines require at least three flexible members32-although more are generally provided in order to increase thiseffectiveness.

A typical height for these flexible members is approximately 2 /2 in.,this height has been found to yield excellent results. Obviously largeror smaller members can be used without departing from the spirit of theinvention as defined in the appended claims.

The beneficial effects achieved by providing a plurality of flexiblemembers can be explained as follows:

Let us suppose to this end that only one flexible member is provided, ofa height equivalent to the sum of the heights of the three flexiblemembers 32', and 32" and 32 illustrated.

Generally the eccentric clothes form an eccentric mass of trapezoidalcross section while the displaced mass of water will be of rectangularcross section whereby the respective centre lines of action of thecentrifugal forces are not at the same height (the centre of thetrapezoid is not at the same height as the centre of the rectangle).This difference in height causes the basket to be subject to an angulardisplacement in a vertical plane, thereby producing an eccentricitywhich most of the devices of the prior art do not compensate.

From the foregoing it can be seen that the inclusion, as per thisinvention, of a plurality of annular members 32 overcomes the foregoingproblem.

It will be evident, to those skilled in the art that if the annularmembers 32', 32", 32" and 32 are included in a conventional machine,then the drive mechanism thereof can be modified so as to drive thebasket at higher speeds compatible with the better balanced basket.

It will be understood that improvements may be introduced into theembodiment described by way of example and modifications may be made inthe constructions and material employed without departing from the scopeof the invention.

What is claimed is:

1. A balancing ring system for the rotatable receptacle of a machinesuch as the rotary basket of a centrifugal clothes-drying machine, saidrotatable receptacle defining an inner wall face and said machinecomprising means to rotate said receptacle about a substantiallyvertical axis, said inner wall face being subtantially parallel to saidvertical axis, the balancing ring system comprising a plurality ofhollow flexible members axially stacked one above the other tightlyagainst said inner wall face and resting on each other, each of saidmembers defining an annular chamber, at least the portion of each one ofsaid flexible members facing the middle of said receptacle beingconstructed to yield and deform under pressure directly exerted by aload within said receptacle and in contact with the portion of saidflexible members facing the middle of said receptacle, and liquidpartially filling said chambers for automatically balancing the load insaid receptacle and minimizing the vibration thereof during rotation ofsaid receptacle.

2. The system of claim 1, wherein each one of said flexible members isprovided with internal deflectors.

3. The system of claim 1, wherein a plurality of circumferentiallyspaced apart upstanding strips are secured to the outer portion of eachone of said flexible members, said upstanding strips forming, bydeformations, protrusions within said flexible members, when theseflexible members are in operative position in said receptacle, saidprotrusions being of such dimension as to cause increased frictionbetween the internal faces of the flexible members and the liquidcontents thereof.

4. The system of claim 1, wherein a plurality of circumferentiallyspaced apart upstanding strips are secured to the outer portion of eachone of said flexible members, said spaced strips causing at least partof the outer portions of said flexible members to be spaced apart fromsaid inner wall surface, thereby defining channels between said stripsfor circulation of water therethrough when said flexible members are inoperative position in said receptacle.

5. The system of claim 1, including circumferentially spaced apart meanspositioned radially outwardly from the outer portion of each one of saidflexible members, said means forming protrusions within said flexiblemembers, when these flexible members are in operative position in saidreceptacle, said protrusions being of such dimension as to causeincreased friction between the internal surfaces of the flexible membersand the liquid contents thereof.

(References on following page) References Cited UNITED STATES PATENTSAdams 74573 Johnson 210363 X De Remer 210363 Kirby 210--363 X Cahn210-363 X Smith 210363 X 8 2,836,301 5/1958 Bruckman 210363 X 2,964,19212/1960 Brown 210363 3,253,710 5/1966 Engel 210--363 X REUBEN FRIEDMAN,Primary Examiner W. S. BRADBURY, Assistant Examiner US. Cl. X.R. 6823.3;74573

